Explanation:
Why has the Sun been so quiet recently?
No one is sure.
Our Sun
has shown few active regions -- that house even fewer associated
sunspots --
for over a year now, and such a
period of relative calm is quite unusual.
What is well known is that our Sun is in
a transitional period between
solar cycles called a
Solar Minimum,
where solar activity has historically been reduced.
The stark lack of surface tumult is unusual even during a
Solar Minimum, however, and activity
this low has not been seen for many
decades.
A few days ago, however, a
bona-fide
active region -- complete with sunspots
--appeared and continues to
rotate across
the Sun's face.
Visible above, this region, dubbed
Active Region 1002 (AR 1002), was imaged in
ultraviolet light yesterday by the
SOHO spacecraft, which co-orbits the Sun
near the Earth.
Besides the
tranquility on the Sun's surface, recent data from the
Ulysses spacecraft, across the Solar System,
indicate that the intensity of the
solar wind blowing out from the Sun is at a fifty
year low.
Predictions hold, however, that our Sun
will show more and more
active regions
containing more and more sunspots and flares until
Solar Maximum occurs in about four years.